1. Field of the Invention
This invention is directed to novel borated hydroxyalkyl esters of alkyl- or alkenylsuccinimide-derived dithiocarbamic acids as multifunctional ashless dispersants and to lubricant compositions containing same.
2. Description of Related Art
N,N-diorganodithiocarbamates (mostly as metal salts, e.g., antimony, zinc, etc.) are commercially available as multifunctional antioxidant, antiwear and corrosion inhibitor additives. However, materials such as 4,4'-methylenebis (dibutyldithiocarbamate) have been variously described in the literature as EP/antiwear/rust inhibiting; EP/antiwear; sludge dispersant/antiwear/rust inhibiting and antiwear/friction reducing compositions. Also, mixtures of this material admixed with other additives are commercially available in compositions described as antioxidant and antiwear additives. See U.S. Pat. Nos. 4,879,054, 4,655,949 and 4,648,885. Furthermore, it is known that ashless thiophosphates derived from dithiocarbamates are effective multifunctional antiwear/antioxidant additives for lubricants. Similarly, alkyl- or alkenylsuccinimides are well known in the art as ashless dispersants for lubricants and fuels, in which capacity they function primarily as dispersants to minimize sludge accumulation on engine parts.